HTML API: Fix finding bookmarks set on closing tag WP_HTML_Tag_Processor.

Setting a bookmark on a tag should set its "start" position before the opening "<", e.g.:
{{{
<div> Testing a <b>Bookmark</b>
----------------^
}}}

The previous calculation assumed this is always one byte to the left from `$tag_name_starts_at`.

However, in a closing tag that index points to a solidus symbol "/":
{{{
<div> Testing a <b>Bookmark</b>
----------------------------^
}}}

The bookmark should therefore start two bytes before the tag name:
{{{
<div> Testing a <b>Bookmark</b>
---------------------------^
}}}

This changeset achieves this by:
* Using the correct starting index for closing tag bookmarks.
* Adding `array( 'tag_closers' => 'visit' )` in `WP_HTML_Tag_Processor::seek()`.

Follow-up to [55203].

Props zieladam, dmsnell, flixos90.
Fixes #57787.
See #57575.

git-svn-id: https://develop.svn.wordpress.org/trunk@55407 602fd350-edb4-49c9-b593-d223f7449a82

Author: hellofromtonya

src/wp-includes/html-api/class-wp-html-tag-processor.php

@@ -722,7 +722,7 @@ public function set_bookmark( $name ) {
 		}
 
 		$this->bookmarks[ $name ] = new WP_HTML_Span(
-			$this->tag_name_starts_at - 1,
+			$this->tag_name_starts_at - ( $this->is_closing_tag ? 2 : 1 ),
 			$this->tag_ends_at
 		);
 
@@ -1504,7 +1504,7 @@ public function seek( $bookmark_name ) {
 		$this->bytes_already_parsed = $this->bookmarks[ $bookmark_name ]->start;
 		$this->bytes_already_copied = $this->bytes_already_parsed;
 		$this->output_buffer        = substr( $this->html, 0, $this->bytes_already_copied );
-		return $this->next_tag();
+		return $this->next_tag( array( 'tag_closers' => 'visit' ) );
 	}
 
 	/**

tests/phpunit/tests/html-api/wpHtmlTagProcessor-bookmark.php

@@ -63,6 +63,28 @@ public function test_seek() {
 		);
 	}
 
+	/**
+	 * @ticket 57787
+	 *
+	 * @covers WP_HTML_Tag_Processor::seek
+	 */
+	public function test_seeks_to_tag_closer_bookmark() {
+		$p = new WP_HTML_Tag_Processor( '<div>First</div><span>Second</span>' );
+		$p->next_tag( array( 'tag_closers' => 'visit' ) );
+		$p->set_bookmark( 'first' );
+		$p->next_tag( array( 'tag_closers' => 'visit' ) );
+		$p->set_bookmark( 'second' );
+
+		$p->seek( 'first' );
+		$p->seek( 'second' );
+
+		$this->assertSame(
+			'DIV',
+			$p->get_tag(),
+			'Did not seek to the intended bookmark location'
+		);
+	}
+
 	/**
 	 * WP_HTML_Tag_Processor used to test for the diffs affecting
 	 * the adjusted bookmark position while simultaneously adjusting